Nowadays, GIS are widely used in different fields improving the effectiveness of work of many specialists and providing fast and objective results for the further analysis. In this respect, the use of GIS to map crime seems to be particularly important since GIS crime mapping originates from earlier police crime maps, when police used hardcopy pin maps to chart criminal activity. However, these early maps had serious disadvantages compared to GIS crime mapping. To put it more precisely, they were static, and as the crime rates increased, they grew more and more difficult to maintain. As a result, in recent years due to the rapid development of IT and user-friendly software, manual crime mapping gave way to computerized crime mapping.
In such a situation, it is quite natural to use GIS to map crime in certain areas in order to increase the effectiveness of the work of police and analysts who target at the minimization of the level of crime. It will also help better understand the current trends and forecast the further development of criminal situation.
Requirement and the aim of the report
Obviously, in order to prove the effectiveness of GIS to map crime, it is necessary to know how to apply GIS in this field, i.e. in the criminal justice field focusing on the crime mapping in certain areas. Furthermore, it will also need to clearly define the types of data sets required for an application of GIS to crime mapping. At the same time, it is also necessary to carefully analyze the use of GIS in crime mapping in order to be able to make a definite conclusion as for its effectiveness and perspectives of its use. Consequently, the main goal of this report is to analyze the possibility of applying GIS to map crime and its effectiveness.
In this respect, it should be pointed out that GIS may be used to crime mapping since GIS can link database software to graphic software to create visual images of various types of data in map format. In fact, it is a unique tool for analyzing physical space and conveying perspective. Presenting data in a form of a map helps specialists understand the significance of where, when and by whom crimes are committed.
At the present moment, it is possible to collect an enormous amount of data and, what is more, the need in GIS crime mapping increases as the crime rates have led to the increase need to organize, sort, analyze and disseminate data. In such a situation GIS crime mapping helps deliver data in a more efficient and instructive manner.
On developing GIS to map crime, it is necessary to point out that GIS software applied in this field should represent data on a map using points, lines, and polygons. Features that can be represented as points include streetlight poles, crime events and bus stops.
In this respect, it should be sad that streetlight poles represented on the map can in a combination with crime events can reveal the fact to which extent the enlightenment of streets can affect crimes. In other words, it will be possible to find out whether enlighten territories are less exposed to crimes or, probably, streetlight poles can decrease the risk of the commitment of a crime as offenders prefer dark streets where the risk of being arrested or face some resistance from the part of a victim is higher. As for the bus stops they are also essential as similarly to the data concerning streetlight poles, bus stops can inform a researcher about the presence of public on the crimes. To put it more precisely, it will be possible to learn whether such places as bus stops, where people are actually waiting for a bus, are good place to commit crimes or probably the presence of ”˜undesirable’ witnesses may prevent offenders from committing a crime, or, in contrast, whether bus stops can attract offenders as a place where potential victim can be exposed to criminal attack. Anyway, for both sorts of data, the collection of data of crime events is of a paramount importance since these data provide an opportunity to analyze the basic trends in crime events and interlink them with other data. For instance, it would be possible to find the areas of the higher risk of possible criminal attack, as well as find out possible solutions helping decrease such a risk.
Bus routes, streets, and rivers may be represented using lines, while counties, states and ZIP codes may be depicted using polygons. All these data are primarily needed to clearly localize the geography of crime. Practically, it means that bus routes and streets presented on the suggested crime map can reveal the areas that are more exposed to crime commitment. In other words, it will be possible to reveal what areas are more dangerous from the point of view of the risk of being offended by a criminal. Rivers are also important since they have to be presented on the map as a potentially risky area or kind of borderlines between areas where crime rates are different. It means that potentially rivers, or river banks, may be scenes of crimes if they are not sufficiently secured and if the rate of crimes in the given area is high. Similalry counties, states, and ZIP codes can be also used to localize crimes and find out areas where the rates of crimes are higher or lower that can help better analyze the situation and reveal the causes of such disparities. Basically, GIS software is designed to capture, store, manage, integrate, and manipulate various layers of data, including those mentioned above, allowing the user to visualize and analyze data in a spatial environment as may be seen in the Exhibit 1, for instance.
Obviously, on creating GIS, it is necessary to remember that GIS should contain base information that orients the map to the reader. For instance, the base information should include roads and state and county boundaries. In this respect, it should be said that the information from the road atlas may be used to create an effective GIS crime mapping.
Furthermore, it should be said that in GIS, a database can represent a layer of information and that can be expanded to create additional layer. For instance, the OVC Subgrant Award Report System (SARS) could be one layer, with the location of all subgrantees defined as individual points on that layer. Another layer of data can be added by querying the SARS database for a particular type of service provider, such as programs for survivor of homicide victims. This additional layer would be mapped using a different color or graphic symbol.
It should be pointed out that GIS is really important since it gives users the ability to analyze multiple layers of information. As a result, it is not only possible to create additional layers from a single database, they can also integrate disparate data sets from other sources such as police departments, planning and housing agencies, and the tax assessor’s office (Exhibit 2). Each agency’s data would become another layer of information in GIS. With this layering of information, it is possible to discern spatial relationships among previously dissociated data. For instance, the data of SARS layer information could be overlaid with incidents of domestic violence cases and locations of public transportation systems. With this displayed information it is possible to examine how accessible services and the criminal justice system are for domestic violence victims.
Furthermore, GIS can pinpoint the physical location of features in every layer. It allows an administrator to conduct spatial searches or queries in addition to tabular database queries. For instance, a tabular database query can retrieve information about increase or decrease in the number of crime victim compensation claims submitted in a particular area.
Also it should be pointed out that GIS also require agency-specific data. In this respect, it is worthy of mention that if an agency collect data via Excel, Access, Pro, Paradox, or any other type of spreadsheet or database management system, the data have potential to be used in GIS, but must have a geographic reference. In general, ZIP codes, street addresses, or x-y coordinates are used to link data to the map by geocoding, or plotting on a map, the data. For instance (Exhibit 3), a street address such as 1150 Main Street can be matched against a street centerline file to determine its location. The geocoding function will link an address to its approximate location on the street segment based on its number. For instance, 1150 Main Street would be placed on the even side of the street about halfway between 1100 and 1200 blocks.
It is also noteworthy that in order to protect private or confidential information, sensitive data are geocoded to the street block, ZIP code, or census-tract level rather than the street level to reduce the possibility of identifying an individual from the mapped data.
Speaking about the practical application of GIS to crime mapping and its methodology, it should be said that a variety of maps can be created using GIS software. As for the potential crime map that can be created it is possible to suggest two most common types of maps, namely, pin maps and thematic maps.
As for pin maps, it should be said that pins may be used to identify important locations. It is quite noteworthy that pin maps have long helped police officers patrol neighborhoods and detectives investigate crimes. In such a situation, in the suggested crime map GIS can enable law enforcement agencies to create, update, duplicate, and distribute pin maps more effectively and easier. Administrators of VOCA victim assistance can plot the locations of victim service providers on pin maps to identify gaps in and duplication of services. Victim service providers can display the vicinity of crime victims to better coordinate their efforts with other providers. The pin map is one of the easiest map to create. Exhibit 4 shows the location of all homicides that occurred in Washington DC, in 1994 and 1995. During the two-year period, there were 756 murders and all but one occurred east of the Rock Creek Park. The similar map may be used for nay other area. Although the points on the map only show location, they reveal the spatial significance that cannot be discerned using a tabular query.
Alternatively, it is possible to create a thematic map which can identify the density value of a particular attribute, such as the number of assaults, crime victim service centers, or victim compensation claims in a geographically defined boundary composed of a state, police precinct, county, neighborhood, census tract, or victim service provider catchment area (Exhibit 5). In exhibit 6, density values are used to create a map with shaded colors representing the different values between the boundaries that allow users to examine patterns across selected boundaries. The shading of thematic maps ranges from light to dark, with the lightest shade representing the lowest value and the darkest shade representing the highest value. This particular exhibit (exhibit 6) shows the density of California VOCA subgrantees by county but the similar map may be used for other areas as well.
In such a way, the implementation of GIS software to map crime leads to the higher efficiency of work of police departments as well as justice system at large since data collected may be presented in a more comprehensible form that is much easier for the perception than traditional maps. Moreover, the amount of data that could be potentially analyzed increases substantially and, what is more, it would be practically impossible to make the similar analysis with such amount information if the crime mapping were made manually.
As for the perspective results of the creation of a crime map, it is possible to say that the map will enable the law enforcement agencies, as well as all specialists working on the problem of crime prevention, to better trace the crime location, find out the areas of the higher risk, and even, to a certain extent, understand the causes of crime. For instance, on the basis of the data that could be used in the suggested map, it would be possible to find out what streets are more exposed to crimes, or whether the enlighten streets are safer to citizens, etc. On analyzing these data, it will be possible to develop an effective plan of prevention of crimes in risky areas. For instance, it will be possible to increase the presence of police patrols in the areas where the risk of being offended is particularly high, or if streetlight poles increase safety of streets it will be possible to develop a program to improve the enlightening of streets.
Conclusion and recommendations
Thus, taking into account all above mentioned, it is possible to conclude that GIS may be very helpful for crime mapping. Moreover, it is practically essential in the modern world since it provides excellent opportunity to process and analyze larger amount of data in a shorter term. It is also worthy of mention that there are a variety of methods that could be used for GIS crime mapping which can be applied and implemented in practice. It is important that GIS crime mapping is user-friendly this is why it will be easy to use crime maps created to any user that is very serious advantage of GIS crime mapping compared to manual one. Obviously, GIS crime mapping can potentially improve substantially the work of police department and justice system at large as it will increase the opportunity to better understand when, where and by whom crimes are committed and, consequently, it will be possible to forecast the crimes and prevent them.
This is why it is possible to recommend implementing the suggested crime map as an effective tool which can really help decrease the level of crime rates and improve the situation dramatically in the areas where it is particularly needed. At the same time, it is possible to recommend continuing work on the development more efficient methods of GIS crime mapping in order to make this process even easier and effective.